Piano actions

ABSTRACT

A piano action for transmitting motion individually from a piano key to a hammer which strikes the corresponding string. The hammer is supported on a roller for swinging toward and away from the piano string. A guide bar supports the roller and a thin flexible band extending around the bar and the roller transmits motion from the key to the roller. The hammer, roller and guide bar are mounted on an individual frame which allows the piano action foe each string position to be installed and removed separately. The piano action also includes a toggle device which controls the operation of a backcheck and includes a damper for the string that is operated in coordination with the motion of the hammer.

[451 Mar. 28, 1972 United States Patent Erbert et al.

0 mm on S N O I T C A... mm m Hm NH NH Primary Examiner-Richard B.Wilkinson [73] Assignee: Rolamite, Incorporated, San Francisco,14331314"!Examiner-Lawrence R'Flanklin Calif. Attorney-Bums, Doane,Swecker & Mathis [57] ABSTRACT A piano action for transmitting motionindividually from a piano The hammer is supported on a roller forswinging toward and [22] Filed: May 18, 1970 key to a hammer whichstrikes the corresponding string.

away from the piano string. A guide bar supports the roller and a thinflexible band extending around the bar and the roller transmits motionfrom the key to the roller. The hammer, roller and guide bar are mountedon an individual References Cited frame which allows the piano actionfoe each string position to be installed and removed separately. Thepiano action also includes a toggle device which controls the operationof a UNITED STATES PATENTS backcheck and includes a damper for thestring that is Gilmore...................................

operated in coordination with the motion of the hammer.

84/240 25 Claims, 13 Drawing Figures 2,737,841 3/1956 McShanetal..3,048,074 8/1962 Quednan m asks PATENTEDMAR28 I972 SHEET 2 [IF 6 INVm'rons VIRGIL ERBERT DONALD F. WILKES BY uru, 50m, 2md4'd,-wec (ulMathis ATTORNEYS PATENTEUMARZB I972 SHEET 3 0F 6 INV ENTORS VIRGILERBERT DONALD E WILKES Burns, bow, guuouot, 3mm l gf r PATENTEDHAR28I972 SHEET [1F 6 mvmwons VIRGIL ERBERT DONALD F. WILKES BY ow, Renaud,Donna at 1 A'ITi s v NEYS ame, A

PATENTEUMARZB m2 sum 5 OF 6 I/Illlll m "g n I .lililllt l INVENTORSVIRGIL ERBERT DONALD F. WILKES u ov-AI, bow, ImomQLad iZ BACKGROUND OFTHE INVENTION This invention relates to key operated percussion devices,and more particularly to piano actions for transmitting motion from akey to a movable hammer.

. In a conventional piano, the piano action transmits motion from a keyto a hammer, causing the hammer to swing toward the corresponding stringand after striking the string, a backcheck in the piano action preventsrebound of the hammer beyond a certain distance. The piano action alsoincludes a damper which moves away from the string just before thehammer strikes the string. The components of the piano action areduplicated for each key along the keyboard. It is customary tomanufacture a component individually and then to assemble the componentby hand on the main rail of the piano. After assembly, the piano actionfor each note is adjusted, as necessary.

Conventional piano actions have a large number of components, and thesecomponents are cushioned by individual felts adhesively bounded onappropriate surfaces of the piano action, and in some piano actions,felts are installed in pivoted joints to reduce the noise of the actionto a minimum. In view of the large number of components, including thefelts, and the complexity of the piano actions, the cost ofmanufacturing and assembling these components is relatively high.

In order to gain acceptance of improved piano actions, it is necessaryto maintain the functional characteristics of present piano actions.Conventional piano actions require a certain minimum kinetic energy tobe imparted to the hammer by the key in order to cause the hammer tostrike the string. The hammer must be disconnected from the keyimmediately before striking the string in order to allow an unincumberedrebound of the hammer on the first vibration cycle of the string. Thedamper must remain in contact with the string until immediately beforethe hammer strikes, in order to keep the string from vibratingsympathetically with other strings which may already be vibrating.Another requirement is that after striking the string, the hammersrebound kinetic energy must be immediately absorbed in a noiseless way,in order to be ready for a succeeding strike. Continued depression ofthe key keeps the damper withdrawn to allow the string to vibrate. Allof the strings can be allowed to vibrate simultaneously by pressing thesustain pedal which overrides the damper action on all keys. Depressionof the soft pedal decreases the kinetic energy imparted to the hammer byany key that is struck while the pedal is depressed.

SUMMARY OF THE INVENTION In view of the difficulties in manufacturingconventional piano actions, it is an object of this invention to providean improved piano action.

Another object of this invention is to provide a piano action havingfewer parts which are easily manufactured and assembled in the pianoaction.

Another object of this invention is to provide a piano action whichrequires a minimum of force for operation and is resistant to wear.

These objects are accomplished in accordance with a preferred embodimentof the invention by a piano action in which the hammer projectsoutwardly from a roller and is movable toward and away from the stringas the roller rolls along a guide surface. Motion of the piano key istransmitted to the guide surface, which produces a corresponding rollingmotion of the roller. A thin flexible band interconnects the roller andthe guide surface to hold these parts together while allowing relativerolling motion. A backcheck operates in response to the displacement ofthe guide surface for temporarily holding the hammer as it reboundsafter striking the string. A damper is also operated in response to themotion of the guide surface and is displaced from the string immediatelybefore the hammer strikes the string. The damper is also capable ofbeing operated independently of the hammer motion when the sustain pedalis depressed.

DETAILED DESCRIPTION OF THE DRAWINGS Several preferred embodiments ofthe invention are illustrated in the accompanying drawings, in which:

FIG. 1 is a side elevational view, partially in cross section, showing apiano action in accordance with one embodiment of this invention;

FIG. 2 is an enlarged cross-sectional view of the piano action along theline 2-2 in FIG. 1;

FIG. 3 is a cross-sectional view of the piano action as in FIG. 1, butshowing the hammer moving toward the string;

FIG. 4 is a cross-sectional view of the piano action as in FIG. I, butwith the hammer in checked position and while the key remains depressed;

FIG. 5 is a perspective view, partially schematic, showing the flexibleband arrangement;

FIG. 6 is a perspective detail view of the hammer roller spring and theband;

FIG. 7 is a detail side elevational view showing the relative motion ofthe hammer roller and associated components;

FIG. 8 is a side elevational detail view of the damper mechanism;

FIG. 9 is a schematic view of the toggle components;

FIG. 10 is a side elevational view, partially in cross section, showinga piano action in accordance with another preferred embodiment of thisinvention;

FIG. 11 is a cross-sectional view of the piano action as in FIG. 10, butwith the hammer in checked position and while the key remains depressed;

FIG. 12 is a cross-sectional view of the the line 12-12 in FIG. 11; and

FIG. 13 is a side elevational view of the piano action as in FIG. 10,but showing a modified connection between the key lever and the drivelever.

piano action along DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Aconventional piano has a keybed on which a plurality of key levers arearranged in side-by-side relation. Each key lever has a key at one endand is connected at the opposite end with the piano action.

Referring to FIG. 1, a conventional keybed 2 is illustratedschematically. The keybed has a balance rail 4 which serves as a fulcrumfor reach key lever 6. A pad 8 extends across the keybed under eachlever for supporting the lever when the keyboard end is raised. Aportion of the key 10 is shown in FIG. 1. The key lever 6 is heldagainst longitudinal movement relative to the balance rail 4 by a pairof pins 12, which allow removal of the key lever 6 merely by lifting thekey lever off of the pins 12.

A string frame 14 supports the strings 16 in an upright position. Thestrings 16 are spaced apart across the length of the string frame 14 atlocations corresponding to each of the key levers 6. An upper rail 18and a lower rail 20 extend along the length of the string frame 14 andat each key lever location, a mounting plate 22 is secured on the upperrail 18 by a screw 24 and on the lower rail 20 by a screw 26.

At each key lever location, a hammer 28 is mounted for swinging movementon a hammer roller 30 by means of a hammer shaft 32. The hammer roller30 is supported on the mounting plate 22 by a system of levers, rollers,and a thin flexible band, which are connected with the mounting plate 22at an upper guide 34 and a lower guide 36. The guides 34 and 36 arepreferably in the form of tabs bent outwardly from the mounting plate 22and have substantially flat guide surfaces. A drive bar 38 is hingedlyconnected with the guide 36 by a thin flexible band 40. The drive barhas a substantially flat surface adjacent the surface of the roller 30.The band 40 passes between the surface of the drive bar 38 and therolling surface of the roller 30. A release bar 42 is also positionedadjacent the hammer roller 30 and has a substantially flat guide surfaceadjacent the rolling surface of the roller 30. The band 40 also passesbetween the surface of the release bar 42 and the rolling surface of theroller 30. A release roller 44 is positioned between the guide 34 andthe end of the release bar 42. The band 40 is tensioned to hold thevarious components together, while allowing the components to rollrelative to each other, and the band 40 is secured on the guide 34.

The end of the key lever 6 has a peg 46 for transmitting mo tion fromthe key lever to the piano action. A drive roller 48 is interposedbetween the peg 46 and the drive' bar 38. The band 40 passes between theguide bar 38 and the roller 48 and urges the roller against the drivebar. A damper bar 50 extends along the key bed 2 in front of the strings16 and has a lever 52 which is connected with the sustain pedal of thepiano, so that when the pedal is depressed, the lever 52 rotates in acounterclockwise direction as viewed in FIG. 8. A damper coupling 54 issecured on the bar 50 and a damper shank 56 extends upwardly from thedamper coupling 54. A damper roller 58 is interposed between the side ofthe damper shank 56 and the curved end of the drive bar 38. The dampercoupling 54, the damper shank 56 and the damper roller 58 are heldtogether for relative rolling motion by the band 40. A damper head 60 issupported from the upper end of the damper shank 56 by a rod 62. Theband is clamped against the interior surface of the coupling 54 by aspacer 64 which is gripped by grooves in the coupling.

A single band interconnects and supports the various components of thepiano action, as shown schematically in FIG. 5. The opposite ends 40aand 40b of the band are secured to the upper surface of the drive bar 38by means of a screw 41, after applying tension in the band. The portion40c of the band extends across the curved surface of the roller 30 andis connected with the portion 40d on the surface of the release bar 42.The portion 40e extends around the roller 42 and extends along the lowersurface of the guide 34. The portion 40f of the band is looped over theguide 34 and may be secured against slippage by applying a suitablefastener between the guide 34 and the band 40. A portion 40g extendsaround the periphery of the release roller 44 and the band also islooped around the release bar 42 with the portion 40h being on the outersurface of the release bar. The band is also looped around the hammerroller and has a hole 40i through which the hammer shaft 32 extends. Aportion 40j extends around the curved surface of the hammer roller 30and along the upper surface of the drive bar 38. The portion 40k islooped over the guide 36 and extends along the lower surface of thedrive bar 38. A portion 401 of the band is looped around the drive roll48. The damper roll 58 is retained between portions 40m and 40n of theband and the portion 400 extends around the damper shank 56. The portion40;; is also looped around the damper coupling 54 and clamped in thecoupling 54 by the spacer 64.

As shown in FIG. 5, the adjacent components of the piano action roll onthe surfaces of the band 40, while the band tension maintains thecomponents in engagement with each other. Since there is no relativesliding between components and the band, the piano action has virtuallyno frictional drag and the parts are not subjected to wear. Also, if anydirt particles should be present on the band or component surfaces, thecomponents merely roll over the particles and there is no interferencewith the action.

The upward displacement of the peg 46 by depressing the opposite end ofthe key lever 6 transmits motion through the drive roll 48 to the drivebar 38, thereby swinging the drive bar about its right end, as viewed inFIG. 1. The release bar 42 cannot move upwardly when the drive barbegins to swing upwardly because the upper end of the release barengages the release roller 44. Thus, the hammer roller pivots about theintersection of the band at the surface of the release bar, but sincethe band prevents slippage between the surface of the drive bar 38 andthe rolling surface of the roller 30, the roller 30 must also pivot atthe'intersection of the band between the roller 30 and the drive bar 38.As a result, the upward force transmitted by the drive roller 48 isexerted on the hammer roller 30, from which it is transmitted to therelease bar 42 in a direction at substantially right angles to thedirection of swinging of the drive bar 38. This movement is shown inFIG. 7 with in full lines in FIG. 7. It can be seen that the left end ofthe 1 drive bar 38 moves upwardly, while the lower end of the releasebar 42 swings toward the left. It should also be noted that the centerof the roller 30 follows a path that is approximately a straight lineextending at about 45 to the line of motion of the peg 46. This upwardmovement of the hammer roller 30 is necessary for operation of thebackcheck feature, as will explained below.

In order to decouple the motion of the roller 30 from the motion of thekey lever 6, a toggle device is provided. The toggle includes therelease bar 42 and the release roller 44 which rolls along the surfaceof the guide 34. The release roller 44 bears against a cushioned stop 66on the mounting plate 22 and another stop 68 is provided adjacent therelease bar 42. The bar has an adjustment screw 70 which extends throughthe bar and the end of the screw pushes against the inside of the band,which in turn engages the stop 68. The band 40 has a corresponding slotto expose the slotted end of the screw 70. By turning the screw, the thedistance between the release bar and the stop can be adjusted.

When the release bar 42 and the roller 44 are in the position shown infull lines in FIG. 9, the upward force on the roller 30 is transmittedthrough the band to urge the bar 42 upwardly against the roller 44 alongthe axis T Since the roller 44 rolls on the surface 34, the reactionforce on the end of the bar 42 is applied along the axis T As a result,the roller 44 is urged to roll toward the left where it engages the stop66. As the key lever 6 moves upwardly, however, the hammer roller 30progressively swings the lower end of the bar 42 about the stop 68,while continuing to exert an upward force on the bar. When the barreaches the position shown in full lines in FIGS. 3 and 9, the axes Tand T coincide and the roller 44 is not urged by the force of the roller30 to move in either direction. However, displacement of the roller 30toward the left, as viewed in FIG. 9, immediately causes the mutualsupport between the end of the bar and the roller 44 to become unstable,and the roller rolls toward the right, carrying the bar 42 with it. Theupper end of the bar 42 swings in the direction of the arrow in FIG. 3,thereby relieving the resistance previously provided by the bar againstthe roller 30, and the roller freely rolls along the surface of thedrive bar 38. The motion of the hammer roller 30 allows the hammer 28 tostrike the string 16 and to rebound freely.

The backcheck feature includes a hammer check 71 which extends outwardlyfrom the shaft 32. A checkpad 72 is supported on a bracket extendingoutwardly from the mounting plate 22 in position to engage acorresponding felt pad on the hammer check 71 when the hammer 28rebounds from the string 16. As shown in FIG. 3 in full lines, thehammer check 71 passes under the pad 72 before the bar 42 has releasedthe roller, and in moving from the position shown in full lines to theposition shown in phantom lines in FIG. 9. At the time the toggle lever42 releases, the end of the drive bar 38 is not at its extreme upwardposition, but is able to swing upwardly a distance sufficient to bringthe hammer check 71 into engagement with the pad 72 as the hammer 28rebounds from the string 16. Upward movement of the drive bar 38 islimited by stops under the key lever 6. As long as the key remainsdepressed, the end of the drive lever 38 is elevated and maintains thehammer check 71 in engagement with the pad 72, as shown in FIG. 4. Assoon as the key is released, the roller 48 and the drive bar 38 dropdownwardly to the position shown in FIG. 1, thereby moving the hammercheck 70 away from the pad 72 and allowing the hammer to swing back tothe position shown in FIG. 1. The instantaneous pivot axis for thehammer shaft 32 is at the intersection of the band between the roller 30and the drive bar 38, so that the hammer 28 has a greater effectivelength, than it would, if the hammer had a fixed pivot. Therefore, it ispossible to shorten the actual length of the hammer shaft 32 to reducethe overall height of the piano action without adversely affecting thequality of performance.

As shown in FIGS. 5, 6 and 7, a leaf spring 74 is provided for returningthe release bar 42 from the position shown in FIG. 4 to the positionshown in FIG. 1. The leaf spring has a tongue 76 which is wrapped on theouter surface of the roller 30 and extends between the band portion 40dand the surface of the roller 30. As shown in FIG. 6, the tongue 76extends upwardly along the band portion 40d. Since the band 40 ismaintained in tension, spring force in the tongue 76 is ineffective torotate the lever when the roller 30 is in the position shown in fulllines in FIG. 7. As the roller rolls back to the position shown indotted lines in FIG. 7, the end of the tongue 76 is progressivelyuncovered. The length of the tongue between its free end and theintersection of the band portions 40 between the lever 42 and the roller30 applies a counterclockwise torque on the lever 42 about the bandintersection, the force of the return spring 76 is sufficient to causethe lever to pivot and to bring the roller 44 back to the position shownin FIG. I. This resetting of the release lever occurs while the hammershaft 32 is moving away from the backcheck pads.

The leaf spring 74 also includes a pair of tongues 78 which overlie theband 40 at the movable end of the drive bar 38. The tongues 78continually urge the roller 30 to rotate in a clockwise direction asviewed in FIG. 7.

The damper 60 is pulled away from the string 16 immediately before thehammer 28 strikes the string. This is accomplished by the arrangement ofthe roller 58 and the cured end of the drive bar 38. As shown bycomparing FIGS. 1 and 3, during the initial upward movement of the endof the bar 38, the roller 58 is displaced only a short distance towardthe right as it rolls across the end of the bar. As soon as the bar 38swings upwardly from the position shown in FIG. 3, however,

the roller 58 accelerates because the slope at the end of the barincreases in the direction of movement of the roller 58 as the rollerapproaches the lower surface of the bar 38. Thus, the damper head 60quickly moves away from the string 16 as the hammer 28 approaches thestring 16. A stop 80 is provided on the mounting plate 22 to limitmovement of the rod 62.

The damper for each key position can also be operated by means of thesustain pedal. A shaft 82 is rotated by means of a link connected withthe sustain pedal (not shown) and the arm 52 is secured on the shaft 82for swinging the damper bar 50in the direction of the arrow in FIG. 8.The roller 48 allows the damper shank 56 to pivot from the positionshown in full lines in FIG. 8 to the position shown in phantom lines inFIG. 8. When the damper of all of the strings is displaced by thesustain pedal, the roller 58 still allows relative motion of the drivebar 38 independent of the position of the damper shank 56 and does notinterfere with the action.

In order to soften the percussion of the hammer 28, a conventionalloudness rail 84 extends across the piano actions and is operated bymeans of a lever 86 connected with the loudness pedal so that in aconventional manner the loudness rail 84 can be displaced to theposition shown in phantom lines in FIG. 4. In this position, the hammershaft 32 does not swing through as great an arc as when the loudnessrail 84 is retracted to the position shown in full lines in FIG. 4. Thusthe kinetic energy imparted by the key lever is reduced.

In operation, when the piano action is initially in the position shownin FIG. 1, depressing lifts the drive rolls 48 and causes the hammerroller 30 to rotate in a counterclockwise direction as the roller movesupwardly along an inclined path. When the hammer 28 approaches thestring 16, the roller 58 draws the damper head 60 away from the string(FIG. 3). The toggle releases the hammer, preferably at about one-eighthinch before the hammer strikes the string, and the hammer rebounds untilthe backcheck pad 72 engages the hammer check 71, preferably with thehammer spaced about fiveeighths of an inch away from the string (FIG.4). As soon as the key is released, the bias provided by the leaf spring74 urges the hammer roller to rotate in a clockwise direction as thehammer check drops away from the pad 72. During the return travel of thehammer roller 30, the release lever 42 is AInI the key is depressed.

Since the hammer roller and associated components are mounted on theplate 22, the action for each key position can easily be removed forrepair or replacement and this unitary arrangement also facilitatesinitial assembly of the piano. The hammer 28, hammer roller 30, releaselever 42, roller 44, the drive bar 38, the drive roller 48, the dampershank 56, damper roller 58 and coupling 54 all can be assembled togetherwith the band on the mounting plate 22 and installed merely by fasteningthe screws 24 and 26 to the upper and lower rails 18 and 20 and applyingthe damper coupling over the sustain bar 50. The key lever 6 is theninstalled by inserting the end of the lever between the roller 48 andthe pad 8 and then swinging the lever down so that the pins 12 projectthrough the sockets in the lever. The position of the toggle can beadjusted after assembly by turning the adjustment screw 70 which isaccessible through the slot in the band 40. Other adjustments can easilybe made by bending the brackets on the mounting plate to change slightlythe position of the components. The rod 62 for the damper can also bebent, if necessary. Another preferred embodiment of the invention isillustrated in FIGS. 10 to 13. Referring to FIG. 10, the keybed 2supports a key lever 6 for swinging movement about a fulcrum. When thekey is depressed at the outer end of the lever, the inner end of thelever in which a peg 46' is mounted swings upwardly to actuate the pianoaction for the selected note. A pad 8 under the end of the key lever 6cushions the decent of the lever 6.

The piano action for each note is mounted as a modular unit on amounting plate 90. An elongated channel extends across the length of thestring frame and is supported in fixed relation to the keybed 2'. Anangle bar 94 extends across the string frame parallel to the channel 92and is supported in fixed relation to the keybed 2. The mounting plateis secured to the upper rail 92 and the lower rail 94 by screws 96 and98, respectively. The mounting plate 90 has mounted blocks 100 and 102which are riveted to the mounting plate 90. The block 100 forms a guidesurface 104 for a release roller 106. A cushion strip 109 limitsmovement of the roller along the surface 104 in one direction and a tabis bent outwardly from the mounting plate 90 to form a stop 111 limitingmovement of the roller 106 in the opposite direction. The stop 11]preferably is covered with a resilient material to absorb energy whenengaged by the roller 106.

A release bar 108 extends between the release roller 106 and a hammerroller 110, corresponding to the release bar 42 I and hammer roller 30of the embodiment illustrated in FIG. 1.

A bracket 112 extends in overlapping spaced relation with the mountingplate 90 and one side of the bracket 112 forms a guide surface 114 for adrive bar 116, corresponding to the drive bar 38 in the embodiment ofFIG. 1. A drive roller 118 is positioned between the drive bar 116 andthe peg 46' on the key lever. A single elongated thin flexible bandencircles the release roller 106, the release bar 108, the hammer roll110, the drive bar 116, and the drive roller 118 in the same manner asthe corresponding portions of the band 40 supports the correspondingelements, as shown in FIG. 5. The band 120 is looped around the side ofthe block 100 that forms the guide surface 104 in the same manner as theband portion 40f is secured on the upper guide 34. Similarly, the band120 is looped around the side of the block 112 which forms the guidesurface 114 in the same manner as the portion 40k of the band is loopedover the lower guide 36 in the embodiment of FIG. 1.

The hammer roller has a leaf spring 122 applied over the band 120. Theleaf spring 122 has substantially the same shape as the spring 74 shownin FIGS. 5 and 6, and performs substantially the same function. A hammershaft 124 is supported at its lower end in a socket formed in the hammerroller 110. The upper end of the shaft 124 supports a conventionalhammer 126. A hammer check 128 is secured in a socket in the hammerroller 110 adjacent the hammer shaft 124. The

hammer check extends forwardly in position to engage a felt pad 130 onthe upper rail 92 as the hammer 126 rebounds away from the string 16,thus the hammer checks holds the hammer at a short distance away fromthe string as long as the key is depressed. When the key is released,the hammer checks moves away from the pad 130, allowing the leaf spring122 to return the hammer to the position shown in FIG. 10.

The damper 132 is supported on a rod 134 that is mounted at its lowerend in a damper bar 136. A leaf spring 138 is secured at one end on theblock 102 and at the opposite end on the damper bar 136. A damper roller140 is interposed between the damper bar 136 and the drive bar 116. Athin flexible band 142 is secured at one end on the lower surface of thebar 116 and is wrapped around the roller 140 and secured on the damperbar 136. The leaf spring 138 is resiliently flexed, as shown in FIG. 10,urging the damper bar 136 downwardly and toward the end of the drive bar116. This imposes sufficient tension in the band 142 to retain theroller 140, and to hold the damper 132 against the string 16. Inaddition, the roller is fixed to the band by means of pins.

The damper moves away from the string immediately before the hammer 126strikes the string. As shown in FIG. 11, as the drive bar 116 swingsupwardly, in response to upward movement of the key lever, motion istransmitted to the roller 140 against the force of the leaf spring 138.The roller 140 is displaced toward the left, causing the damper bar 136to rotate in a clockwise direction, as viewed in FIG. 11, about thelower end of the spring 138. This motion is transmitted through the rod134 to the damper 132, causing the damper to swing away from the string16 until it engages a pad 144 on the upper rail 92. When the key lever 6is released, the drive bar 1 16 swings downwardly to the position shownin FIG. 10, and the force of the spring 138 urges the roller 140 to rollin a clockwise direction, thereby returning to the position shown inFIG. 10 with the damper 132 in engagement with the string 16'.

It is also necessary to provide for holding the damper 132 of all of thenote positions simultaneously away from the corresponding strings. Thisis accomplished in the embodiment of FIG. 11 by a movable bar thatextends parallel to the upper and lower rails 92 and 94. The bar 144 isconnected with the foot pedal of the piano so that upon depression ofthe foot pedal, the bar 144 moves from the position shown in FIG. 10toward the left where it engages a padded surface 146 on the damper bar136. Although the drive bar 116 remains in the position shown in FIG.10, the movement of the sustain bar 144 causes the damper bar 136 toswing about the end of the spring 138 to displace the damper 132 awayfrom the strings 16'.

In operation, when the key is depressed, the key lever 6' swingsupwardly toward the position shown in FIG. 11. This motion of the keylever is transmitted through the peg 46 and through the drive roller 118to the drive bar 116, causing the drive bar to swing in a clockwisedirection about the side 114 of the block 112. As the drive bar 116swings upwardly, the hammer roller 110 rolls in a counterclockwisedirection along the surface of the bar 116, while at the same timemoving diagonally upward. The force of the key lever 6' is transmittedthrough the hammer roller 110 to the release bar 108, as the bar pivotsabout the release roller 106, in the same manner as the release bar 42pivots about the release roller 44. Ultimately, the release bar 108engages the stop 68' on the block 102 and the roller 106 is released formovement toward the stop 110. At the same time, the damper 132 has beendisplaced away from the string by motion of the roller 140 by the drivebar 116.

After striking the string 16, the hammer rebounds freely as a result ofthe release action of release bar 120 and roller 106, until thebackcheck 1 28 engages the pad 130 to hold the hammer against furthermovement away from the string and to absorb the rebound energy of thehammer. As soon as the key is released, the end of the lever 6' returnsto the position shown in FIG. 10 and the backcheck 128 moves away fromthe pad to allow the hammer to move against the loudness rail 84', asshown in FIG. 10. An extension of spring 122 bears against bar 108urging it and the release roller 106 against stops 108 and 68. At thesame time, the drive bar 116 returns the damper 132 into engagement withthe string 16' and the hammer 136 is ready to strike the string again.

In a modified form of the embodiment of FIG. 10, the height of thehammer 126 over the keybed' can be increased by increasing the length ofthe hammer shaft 124 and by inserting an extension 148 between the peg46 and the drive roller 118. The extension 148 has a socket which gripsthe drive roll 118 to hold the extension on the roller. A felt pad isprovided on the extension 148 in position to engage the peg 46 As thelever 6 moves upwardly, the forces are transmitted through the extensionto swing the drive bar 116 in the same manner as described with respectto the form of this embodiment illustrated in FIG. 11.

FIG. 13 also illustrates the action of the sustain bar 144 in displacingthe damper 132 of each, note position away from the string. The sustainbar is displaced by the pedal from the position shown in dotted lines inFIG. 13 to the position shown in full lines, thereby swinging the lowerend of the damper bar 136 about the release spring 138. The force of thespring 138 maintains the bar in engagement with the sustain bar 144.

The band 40 of the embodiment shown in FIG. 1 and the bands 120 and 142of the embodiment shown in FIG. 10 may be formed of any thin flexiblematerial which has sufficient strength and tension to sustain the forcestransmitted through the band. Suitable materials for the band includethin sheet metal, such as beryllium-copper alloys and stainless steel,flexible tapes made of .glass fibers impregnated with synthetic resins,such as polytetrafluorol ethylene, Mylar, or other plastic tapes andcloth tapes.

The piano action of this invention allows each key position to beassembled as a modular unit and then installed in the piano. It is notnecessary to manufacture different sizes and shapes of parts for eachkey position. Another important advantage of the apparatus of thisinvention is that the components are primarily formed of simple shapesthat are easy to manufacture by extruding, molding or milling. Therollers, for example, may be cut from rods and the various levers may bemolded of plastic. Dimensions of the parts are not particularlycritical. The most critical dimensions can be confined to the band whichcan be manufactured to close tolerances by conventional chemical etchingtechniques. The assembly of this invention provides a piano action inwhich the keyboard touch or feel is substantially identical with that ofconventional piano actions. There is essentially no wear on thecomponents, except for the felts, and the components should not beadversely affected by changes in climate.

While this invention has been illustrated and described in a preferredembodiment, it is recognized that variations and changes may be madetherein without departing from the invention set forth in the claims.

What is claimed is:

1. A piano action comprising:

a roller having a rolling surface;

a hammer fixed on said roller;

mounting means;

guide means including a pair of guide bars mounted for swinging movementon said mounting means, said guide bars each having a guide surface;

means restricting said roller to rolling along said guide surfaces;

a piano key;

drive means interconnecting said piano key with one of said guide barsfor swinging said one guide bar;

whereby in response to said swinging of said guide bar the roller rollsalong said guide surfaces and said hammer moves to strike a pianostring.

2. The piano action according to claim 1 wherein said drive meansincludes band means between said roller and said guide means, said bandmeans being secured against longitudinal slippage relative to saidroller surface while allowing said roller to roll relative to said guidesurfaces, said band means urging said roller toward said guide means.

3. The piano action according to claim 1 including means mounting abackcheck pad at a fixed location, and a hammer check on said hammer,said guide means including means for maintaining said hammer checkspaced from said backcheck pad while said hammer moves in the directionof a piano string and for moving said hammer check into engagement withsaid backcheck pad upon swinging said hammer in the opposite direction.

4. The piano action according to claim 3 wherein one of said guide barsis movable toward and away from said backcheck pad, said roller swingingsaid hammer in the direction of said string in response to displacementof said guide bars whereby the displacement of the guide bars causes thehammer check to engage the backcheck pad as the hammer rebounds.

5. The piano action according to claim 1 including damper means forengaging a piano string and damping vibration, and means for disengagingsaid damper means from a piano string in response to said rollerswinging said hammer in the direction of a piano string.

6. The piano action according to claim 1 wherein said mounting meansincludes a mounting plate, said drive means including a band, said guidebars being pivotally supported on said mounting plate by said band andsaid roller being supported on said guide bars by said band, whereby thecomponents of the piano action may be assembled on the mounting platebefore being installed in the piano.

7. The piano action according to claim 1 including means urging saidhammer to swing away from said piano string, and including means forrendering said urging means ineffective when said hammer is in theproximity of a piano string, whereby the hammer swings freely whenstriking and l rebounding from the piano string.

8. A piano action comprising:

mounting means;

guide means including a pair of guide levers mounted for swingingmovement on said mounting means, said guide levers each having a guidesurface;

a roller having a rolling surface;

thin band means extending along said guide surface of each of saidlevers and extending along said rolling surface, said band means beingsupported in tension to cause said roller surface to bear against saidguide surfaces of both levers while restricting said roller to rollalong said guide surfaces without slippage between said surfaces;

a piano key;

drive means interconnecting said key and one of said levers for swingingsaid one lever in response to depressing movement of said key; a hammer;motion transmitting means between said roller and said hammer fordisplacing said hammer toward a piano string in proportion to the extentof rolling of said roller in one direction along said guide surface ofthe respective levers,

whereby the motion of the key is transmitted to the hammer through saidroller.

9. The piano action according to claim 8 wherein said guide surface ofeach lever is substantially straight, said rolling surface of saidroller bearing on said surfaces of the respective levers at first andsecond locations spaced apart circumferentially of said rolling surface,said locations being arranged to apply torque tending to roll saidroller in said one direction along said guide surface of the respectivelevers in response to depressing movement of said key.

10. The piano action according to claim 9, including a resilientlyflexible spring element, said spring element being secured on saidroller and extending along said rolling surface on one side of saidfirst location and extending along said guide surface of one of saidlevers on the opposite side of said 10 7 first location, whereby theportion of said spring element on said rolling surface is biased towardsaid guide surface and urges said roller to roll along said guidesurface in a direction opposite to said one direction.

11. The piano action according to claim 9 wherein said band meansextends across said first and second locations on said rolling surface,the spacing along said rolling surface between said first and secondlocations remaining substantially constant during rolling motion of saidroller along said guide surfaces.

12. The piano action according to claim 8 wherein said band meansincludes a band portion encircling said roller and extending along saidguide surface of each lever in opposite directions from the respectivelocations at which said roller bears against said guide surface, saidband portion being secured against longitudinal movement relative tosaid guide surface and said rolling surface, whereby said band portioncauses said roller to bear against said guide surface while restrictingsaid roller to roll along the guide surface without slippage.

13. A piano action comprising:

a roller having a roller surface;

a first guide lever having a first guide surface;

a second guide lever having a second guide surface;

means for connecting said second guide lever with a piano key formovement of said second lever in response to movement of said key;

a hammer;

means for mounting said hammer on said roller for movement toward andaway from a piano string in response to rolling of said roller meansalong said first and second guide surfaces;

mounting means, said guide levers being movably mounted on said mountingmeans;

a thin flexible band extending along said first and second guidesurfaces and along said rolling surface, said band restrictingdisplacement of said first and second guide surfaces away from saidrolling surfaces while allowing rolling of said roller means along saidsurfaces, said first and second guide surfaces being in closestproximity to said rolling surface at bearing locations spacedcircumferentially along said rolling surface, and

means for holding portions of said band in tension along said guidesurfaces, whereby displacement of said second guide surface by a pianokey lever results in rolling said roller means along said second guidesurface and thereby causing said hammer to strike a piano string.

14. The piano action according to claim 13 wherein said mounting meansincludes hinges between said mounting means and said guide levers, saidhinges includes portions of said band supporting said levers for hingedmovement, said hinges being positioned at hinge locations spaced fromsaid roller surface.

15. The piano action according to claim 13 including a release rollerbetween said first lever and one of said hinge locations, and includingfulcrum means fixed relative to said hinge locations, said fulcrum meansbeing on the opposite side of said first lever from said rolling surfaceand being spaced a shorter distance from said release roller than is theclosest bearing location between said first guide surface and saidroller surface, whereby rolling of said roller surface along said firstand second guide surfaces swings said first lever about said fulcrummeans and displaces said release roller, thereby allowing the hammerroller means to roll freely along said guide surface.

16. The piano action according to claim 15 including spring means forurging said first lever to pivot about said rolling surface upondisplacement of said point of close proximity away from said releaseroller, whereby the first lever is returned from a release position to aholding position.

17. The piano action according to claim 15 wherein said means forholding includes a first mounting surface at said first lever hingelocation, said band being secured on said first mounting surface andencircling said release roller and said first lever to allow rolling ofsaid roller relative to said mounting surface and said lever.

18. The piano action according to claim 17 wherein said means forholding includes a second mounting surface at said second lever hingelocation, said band being secured on said second mounting surface andencircling said second lever to allow swinging of said second leverrelative to said second mounting surface, said first and second mountingsurfaces being provided on a continuous mounting plate extending betweensaid first and second locations.

19. A piano action comprising:

mounting means;

a first lever hingedly mounted on said mounting means at a first hingelocation;

a second lever hingedly mounted on said mounting means at a second hingelocation; said first and second levers each having a longitudinal guidesurface, said levers being arranged for swinging about their respectivehinge locations to positions wherein the guide surface of said firstlev'er extends at substantially right angles to the guide surface ofsaid second lever;

a main roller having a roller surface bearing on both of the respectiveguide surfaces of said levers;

traction means preventing relative sliding between said rolling surfaceand said guide surfaces, said traction means including means formaintaining said rolling surface in bearing relation with both of saidguide surfaces during swinging movement of said levers;

a piano key;

drive means connecting said second lever with said piano key forswinging said second lever in one direction about said second hingelocation by depressing said key, and for swinging said second lever inthe opposite direction while said key raises from a depressed position;

a hammer;

motion transmitting means between said main roller and said hammer fordisplacing said hammer toward a piano string in response to rotation ofsaid roller in one direction relative to said guide surface of saidsecond lever and away from the piano string in response to rotation ofsaid roller in the opposite direction.

20. The piano action according to claim 19 wherein said levers arehingedly mounted for swinging about substantially parallel axes, saidrolling surface being substantially cylindrical and having a centralaxis extending substantially parallel to said lever axes.

21. The piano action according to claim 20 wherein said motiontransmitting includes an arm fixed on said main roller, said hammerbeing spaced from said rolling surface and being fixed on said arm, ahammer check secured on said roller adjacent said arm, means mounting acheck pad at a fixed location adjacent said first lever hinge location,said pad being arranged to be engaged by said check upon rebound fromsaid string while said key is depressed, whereby release of said keyallows said second lever to swing in a direction opposite to said onedirection and thereby to disengage said check from said pad, allowingsaid roller to return to its retracted position.

22. The piano action according to claim 20 wherein traction meansincludes a thin, flexible band extending continuously along said guidesurfaces of said first and second levers and looped around said mainroller and said release roller, said band forming the sole meanssupporting said main roller from movement from said retracted positionto said extended position.

23. The piano action according to claim 20 wherein said mounting meansincludes a cam surface, said cam surface extending transversely of saidfirst lever guide surface and being spaced from said first lever, arelease roller interposed between said first lever and said cam surface,said first hinge location being between said release roller and saidfirst lever, and including a stop positioned adjacent said cam surfacefor engagement b said release roller and a fulcrum in engagement withsar first lever on the side thereof opposite said main roller, said mainroller being capable of rolling along the respective guide surfaces froma retracted position in which the rolling surface bears on therespective guide surfaces at a position remote from said first hingelocation and close to said second hinge location to an extended positionin which the rolling surface bears on the respective guide surfaces atlocations close to said first hinge location and remote from said secondhinge location, said fulcrum pivoting said first lever on movement ofsaid main roller from the retracted position toward the extendedposition.

24. The piano action according to claim 23 wherein the bearing locationbetween said main roller and said first lever is aligned with said firsthinge location along an axis intersecting said cam surface between thepoint of engagement of said release roller and said cam surface and thepoint of engagement between said release roller and said stop, wherebysaid first lever applies torque through said traction means for rotatingsaid roller while said second lever swings in said one direction, untilsaid first lever pivots about said fulcrum sufficiently to cause saidfirst lever to roll said release roller along said cam surface.

25. The piano action according to claim 24 including a spring element onsaid main roller, said spring element extending along said rollingsurface and along said guide surface of said first lever, said springelement being arranged to urge said first lever to displace said releaseroller along said cam surface into engagement with said stop as saidmain roller returns to said retracted position.

1. A piano action comprising: a roller having a rolling surface; ahammer fixed on said roller; mounting means; guide means including apair of guide bars mounted for swinging movement on said mounting means,said guide bars each having a guide surface; means restricting saidroller to rolling along said guide surfaces; a piano key; drive meansinterconnecting said piano key with one of said guide bars for swingingsaid one guide bar; whereby in response to said swinging of said guidebar the roller rolls along said guide surfaces and said hammer moves tostrike a piano string.
 2. The piano action according to claim 1 whereinsaid drive means includes band means between said roller and said guidemeans, said band means being secured against longitudinal slippagerelative to said roller surface while allowing said roller to rollrelative to said guide surfaces, said band means urging said rollertoward said guide means.
 3. The piano action according to claim 1including means mounting a backcheck pad at a fixed location, and ahammer check on said hammer, said guide means including means formaintaining said hammer check spaced from said backcheck pad while saidhammer moves in the direction of a piano string and for moving saidhammer check into engagement with said backcheck pad upon swinging saidhammer in the opposite direction.
 4. The piano action accordiNg to claim3 wherein one of said guide bars is movable toward and away from saidbackcheck pad, said roller swinging said hammer in the direction of saidstring in response to displacement of said guide bars whereby thedisplacement of the guide bars causes the hammer check to engage thebackcheck pad as the hammer rebounds.
 5. The piano action according toclaim 1 including damper means for engaging a piano string and dampingvibration, and means for disengaging said damper means from a pianostring in response to said roller swinging said hammer in the directionof a piano string.
 6. The piano action according to claim 1 wherein saidmounting means includes a mounting plate, said drive means including aband, said guide bars being pivotally supported on said mounting plateby said band and said roller being supported on said guide bars by saidband, whereby the components of the piano action may be assembled on themounting plate before being installed in the piano.
 7. The piano actionaccording to claim 1 including means urging said hammer to swing awayfrom said piano string, and including means for rendering said urgingmeans ineffective when said hammer is in the proximity of a pianostring, whereby the hammer swings freely when striking and reboundingfrom the piano string.
 8. A piano action comprising: mounting means;guide means including a pair of guide levers mounted for swingingmovement on said mounting means, said guide levers each having a guidesurface; a roller having a rolling surface; thin band means extendingalong said guide surface of each of said levers and extending along saidrolling surface, said band means being supported in tension to causesaid roller surface to bear against said guide surfaces of both leverswhile restricting said roller to roll along said guide surfaces withoutslippage between said surfaces; a piano key; drive means interconnectingsaid key and one of said levers for swinging said one lever in responseto depressing movement of said key; a hammer; motion transmitting meansbetween said roller and said hammer for displacing said hammer toward apiano string in proportion to the extent of rolling of said roller inone direction along said guide surface of the respective levers, wherebythe motion of the key is transmitted to the hammer through said roller.9. The piano action according to claim 8 wherein said guide surface ofeach lever is substantially straight, said rolling surface of saidroller bearing on said surfaces of the respective levers at first andsecond locations spaced apart circumferentially of said rolling surface,said locations being arranged to apply torque tending to roll saidroller in said one direction along said guide surface of the respectivelevers in response to depressing movement of said key.
 10. The pianoaction according to claim 9, including a resiliently flexible springelement, said spring element being secured on said roller and extendingalong said rolling surface on one side of said first location andextending along said guide surface of one of said levers on the oppositeside of said first location, whereby the portion of said spring elementon said rolling surface is biased toward said guide surface and urgessaid roller to roll along said guide surface in a direction opposite tosaid one direction.
 11. The piano action according to claim 9 whereinsaid band means extends across said first and second locations on saidrolling surface, the spacing along said rolling surface between saidfirst and second locations remaining substantially constant duringrolling motion of said roller along said guide surfaces.
 12. The pianoaction according to claim 8 wherein said band means includes a bandportion encircling said roller and extending along said guide surface ofeach lever in opposite directions from the respective locations at whichsaid roller bears against said guide surface, said band portion beinGsecured against longitudinal movement relative to said guide surface andsaid rolling surface, whereby said band portion causes said roller tobear against said guide surface while restricting said roller to rollalong the guide surface without slippage.
 13. A piano action comprising:a roller having a roller surface; a first guide lever having a firstguide surface; a second guide lever having a second guide surface; meansfor connecting said second guide lever with a piano key for movement ofsaid second lever in response to movement of said key; a hammer; meansfor mounting said hammer on said roller for movement toward and awayfrom a piano string in response to rolling of said roller means alongsaid first and second guide surfaces; mounting means, said guide leversbeing movably mounted on said mounting means; a thin flexible bandextending along said first and second guide surfaces and along saidrolling surface, said band restricting displacement of said first andsecond guide surfaces away from said rolling surfaces while allowingrolling of said roller means along said surfaces, said first and secondguide surfaces being in closest proximity to said rolling surface atbearing locations spaced circumferentially along said rolling surface,and means for holding portions of said band in tension along said guidesurfaces, whereby displacement of said second guide surface by a pianokey lever results in rolling said roller means along said second guidesurface and thereby causing said hammer to strike a piano string. 14.The piano action according to claim 13 wherein said mounting meansincludes hinges between said mounting means and said guide levers, saidhinges includes portions of said band supporting said levers for hingedmovement, said hinges being positioned at hinge locations spaced fromsaid roller surface.
 15. The piano action according to claim 13including a release roller between said first lever and one of saidhinge locations, and including fulcrum means fixed relative to saidhinge locations, said fulcrum means being on the opposite side of saidfirst lever from said rolling surface and being spaced a shorterdistance from said release roller than is the closest bearing locationbetween said first guide surface and said roller surface, wherebyrolling of said roller surface along said first and second guidesurfaces swings said first lever about said fulcrum means and displacessaid release roller, thereby allowing the hammer roller means to rollfreely along said guide surface.
 16. The piano action according to claim15 including spring means for urging said first lever to pivot aboutsaid rolling surface upon displacement of said point of close proximityaway from said release roller, whereby the first lever is returned froma release position to a holding position.
 17. The piano action accordingto claim 15 wherein said means for holding includes a first mountingsurface at said first lever hinge location, said band being secured onsaid first mounting surface and encircling said release roller and saidfirst lever to allow rolling of said roller relative to said mountingsurface and said lever.
 18. The piano action according to claim 17wherein said means for holding includes a second mounting surface atsaid second lever hinge location, said band being secured on said secondmounting surface and encircling said second lever to allow swinging ofsaid second lever relative to said second mounting surface, said firstand second mounting surfaces being provided on a continuous mountingplate extending between said first and second locations.
 19. A pianoaction comprising: mounting means; a first lever hingedly mounted onsaid mounting means at a first hinge location; a second lever hingedlymounted on said mounting means at a second hinge location; said firstand second levers each having a longitudinal guide surface, said leversbeing arranged for swinging about their respective hinge locations topositions wherein the guide surface of said first lever extends atsubstantially right angles to the guide surface of said second lever; amain roller having a roller surface bearing on both of the respectiveguide surfaces of said levers; traction means preventing relativesliding between said rolling surface and said guide surfaces, saidtraction means including means for maintaining said rolling surface inbearing relation with both of said guide surfaces during swingingmovement of said levers; a piano key; drive means connecting said secondlever with said piano key for swinging said second lever in onedirection about said second hinge location by depressing said key, andfor swinging said second lever in the opposite direction while said keyraises from a depressed position; a hammer; motion transmitting meansbetween said main roller and said hammer for displacing said hammertoward a piano string in response to rotation of said roller in onedirection relative to said guide surface of said second lever and awayfrom the piano string in response to rotation of said roller in theopposite direction.
 20. The piano action according to claim 19 whereinsaid levers are hingedly mounted for swinging about substantiallyparallel axes, said rolling surface being substantially cylindrical andhaving a central axis extending substantially parallel to said leveraxes.
 21. The piano action according to claim 20 wherein said motiontransmitting includes an arm fixed on said main roller, said hammerbeing spaced from said rolling surface and being fixed on said arm, ahammer check secured on said roller adjacent said arm, means mounting acheck pad at a fixed location adjacent said first lever hinge location,said pad being arranged to be engaged by said check upon rebound fromsaid string while said key is depressed, whereby release of said keyallows said second lever to swing in a direction opposite to said onedirection and thereby to disengage said check from said pad, allowingsaid roller to return to its retracted position.
 22. The piano actionaccording to claim 20 wherein traction means includes a thin, flexibleband extending continuously along said guide surfaces of said first andsecond levers and looped around said main roller and said releaseroller, said band forming the sole means supporting said main rollerfrom movement from said retracted position to said extended position.23. The piano action according to claim 20 wherein said mounting meansincludes a cam surface, said cam surface extending transversely of saidfirst lever guide surface and being spaced from said first lever, arelease roller interposed between said first lever and said cam surface,said first hinge location being between said release roller and saidfirst lever, and including a stop positioned adjacent said cam surfacefor engagement by said release roller and a fulcrum in engagement withsaid first lever on the side thereof opposite said main roller, saidmain roller being capable of rolling along the respective guide surfacesfrom a retracted position in which the rolling surface bears on therespective guide surfaces at a position remote from said first hingelocation and close to said second hinge location to an extended positionin which the rolling surface bears on the respective guide surfaces atlocations close to said first hinge location and remote from said secondhinge location, said fulcrum pivoting said first lever on movement ofsaid main roller from the retracted position toward the extendedposition.
 24. The piano action according to claim 23 wherein the bearinglocation between said main roller and said first lever is aligned withsaid first hinge location along an axis intersecting said cam surfacebetween the point of engagement of said release roller and said camsurface and the point of engagement between said release roller and saidstop, whereby said first lever applies torque throUgh said tractionmeans for rotating said roller while said second lever swings in saidone direction, until said first lever pivots about said fulcrumsufficiently to cause said first lever to roll said release roller alongsaid cam surface.
 25. The piano action according to claim 24 including aspring element on said main roller, said spring element extending alongsaid rolling surface and along said guide surface of said first lever,said spring element being arranged to urge said first lever to displacesaid release roller along said cam surface into engagement with saidstop as said main roller returns to said retracted position.